Blue-gray Taildropper (slug) (Prophysaon coeruleum)

CLose up of a Blue-gray Taildropper slug on a wood surface.
An adult blue-gray taildropper found in Cowlitz County. (Copyright 2003 William Leonard)
Category: Molluscs
State status: Candidate
Vulnerability to climate change (More details)


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Climate vulnerability

Sensitivity to climate change


There is limited information regarding the sensitivity of Bluegray taildroppers to climate change. Their main sensitivity is likely to be driven by changes in their preferred habitat – older, late successional, forests with moist ground and a mixture of hardwood and conifer trees. Increases in temperature and decreases in summer rainfall are likely to lead to increased risk of severe fires, which would destroy habitat for this species. Declines in habitat quality could also lead to fragmentation of populations, particularly since slugs are not very mobile, and eventual population declines. Additionally, decreased summer rainfall and increased droughts could lead to changes in soil moisture and availability of fungal populations that this species feeds on.

Confidence: Moderate

Exposure to climate change


  • Increased temperatures
  • Reduced soil moisture and/or changes in precipitation
  • Altered fire regimes
Confidence: Low


This species is identified as a Species of Greatest Conservation Need (SGCN) under the State Wildlife Action Plan (SWAP). SGCN-classified species include both those with and without legal protection status under the Federal or State Endangered Species programs, as well as game species with low populations. The WDFW SWAP is part of a nationwide effort by all 50 states and five U.S. territories to develop conservation action plans for fish, wildlife and their natural habitats—identifying opportunities for species' recovery before they are imperiled and more limited.
This species is identified as a Priority Species under WDFW's Priority Habitat and Species Program. Priority species require protective measures for their survival due to their population status, sensitivity to habitat alteration, and/or recreational, commercial, or tribal importance. The PHS program is the agency's main means of sharing fish and wildlife information with local governments, landowners, and others who use it to protect priority habitats for land use planning.